New Tiny Wireless Temperature Sensor Could Power IoT

A new chip that can power itself using only the energy transmitted by a Wi-Fi signal could have a major impact on the Internet of Things and mobile technology in general. The breakthrough means that the chip doesn’t require a battery, or even a wire, and never needs to be recharged.

The chip (Image: Bart van Overbeeke), developed at the University of Technology at Eindhoven by researchers in The Netherlands, is a tiny wireless temperature sensor weighing only 1.6 milligrams and measuring just two square millimeters, about the size of a grain of sand. Although the most obvious application for the technology will be in developing sensors for IoT applications, the scientists behind the chip said they anticipated a variety of potential uses for it.

Energy Efficient, but Short Range Similar sensors could be used to make smart buildings more energy efficient, the university said in a blog post. “The smart buildings of the future will be full of sensors that will respond to the residents’ every need, and will be as sustainable as possible,” according to the post. “Like heating and lighting that only switches on when someone is in the room. That’s only possible if these sensors are wireless and need no batteries, otherwise in a large building you would have to change the batteries every day.”

Although the current chip has a range of only 2.5 centimeters, the researchers said they expect to be able to extend that distance up to a meter within a year, and eventually reach a goal of five meters. To work, the sensor requires the help of a special router equipped with an antenna capable of transmitting radio waves to power the chip.

The radio signals are targeted on the sensor, which means the router requires minimal energy to work. The sensor is also designed to be as energy efficient as possible.

Painting with Sensors

The sensor also operates beneath a layer of paint, plaster or concrete. This makes the sensor easy to incorporate in buildings, and could be “painted” onto a wall with a normal latex paint, said Peter Baltus, a professor of wireless technology at the university.

The sensor contains an antenna that captures the energy from the router. The sensor stores that energy and, once there is enough, the sensor switches on, measures the temperature and sends a signal to the router. This signal has a distinctive frequency, depending on the temperature measured. The router can then determine the temperature from the frequency.

The same technology could also be used to develop wireless sensors capable of measuring movement, light, and humidity, among other variables. Beyond energy-efficient smart buildings, the potential applications for the technology could include payment systems, wireless identification platforms, and industrial production systems, Baltus said.

Mass production is expected to bring costs down to 20 cents for a single sensor, which should make it relatively easy for companies to adopt the technology once it’s commercialized.